Iridium film growth with iridium tris-acetylacetonate: oxygen and substrate effects

Oxygen and substrate effects on iridium film growth have been investigated by metallorganic chemical vapor deposition (MOCVD), insitu X-ray photoelect ron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Iridium tris-acetylacetonate, Ir(CH3COCHCOCH3)(3), was used as the Ir precursor. High purity CVD Ir films were obtained when t his precursor was co-dosed with oxygen. Without oxygen, the Ir film contain s noticeable carbon. The presence of oxygen not only removes carbon, but al so prevents carbon incorporation from other reactive gas components, such a s acetone. Oxygen also controls the film deposition rate and has a signific ant impact on the him morphology. Substrate effects on the initial growth r ate an evidenced by the fact that the growth rate on a titanium-carbonitrid e (TiCN) surface is significantly higher than that on an SiO2 surface. Sele ctive deposition in the presence of oxygen was also observed; compared to S iO2 and Ta2O5 substrates, no deposition (or very slow deposition) was obser ved on sapphire at 400 degrees C. The topography of films grown on the vari ous substrates was compared using AFM. Ir was roughest when deposited on Si O2 using a low oxygen flow rate. This is because the initial growth of Ir f ilms on SiO2 follows a three-dimensional growth mode on isolated islands. ( C) 1999 Elsevier Science S.A. All rights reserved.